Can you try using the other nic types? I'm most interested in the results with the rtl8139 model.
I have used rtl8139 the first time.Does not work. I think the etherboot is OK. because I can use it to boot from vmware. and the ethereal captured the DHCP offer packet on tap nic. How the tap-win32 and qemu deal with this packet? I can't trace it.